Illumination system and display device

Abstract

A backlight system comprises at least two light-emitting panels ( 1; 11 ) having a front wall ( 2; 12 ), an opposing rear wall ( 3; 13 ) and opposite edge surfaces ( 4, 14; 5, 15 ). At least one of the edge surfaces ( 4; 14 ) is light-transmitting and associated with a plurality of light sources ( 6, 16 ). Light originating from the light sources ( 6; 16 ) is diffused in the panel ( 1; 11 ). Sub-surfaces ( 8, 18 ) of the rear walls ( 3, 13 ) are provided with means for extracting light from the panel ( 1, 11 ). In operation, said sub-surfaces ( 8, 18 ) project light on areas ( 9, 19 ) of an (imaginary) plane ( 40 ) which is positioned parallel to the light-emitting panels ( 1, 11 ). Said projected areas ( 9, 19 ) in the plane ( 40 ) are substantially contiguous. Preferably, said sub-surfaces ( 8, 18 ) are remote from the light-transmitting edge surfaces ( 4; 14 ). Preferably, each of said sub-surfaces ( 8, 18 ) forms a single surface covering half the front wall ( 2, 12 ) of the light-emitting panel ( 1, 11 ). Alternatively, the sub-surfaces encompass a substantial area of the rear walls, the distribution of the means for extracting light from the panel being such that the amount of extracted light changes as a function of the distance to the light-transmitting edge surfaces. Preferably, the light source comprises a plurality of red, green, blue (and amber) LEDs, each preferably having a luminous flux of at least 5 lumen.

What is claimed is:  
     
       1. An illumination system for illuminating a display device, said illumination system comprising: 
       a first light source operable to emit a first band of light;  
       a first light emitting panel including a first light transmitting edge area operable to receive the first band of light, said first light emitting panel further including a first sub-surface on a first wall, said first sub-surface operable to couple at least a portion of the first band of light out of said first light emitting panel,  
       wherein a degree in which the at least a portion of the first band of light is coupled out of said first light emitting panel varies as a function of a distance between said first light transmitting edge area and said first sub-surface;  
       a second light source operable to emit a second band of light; and  
       a second light emitting panel including a second light transmitting edge area operable to receive the second band of light said second light emitting panel further including a second sub-surface on a second wall, said second sub-surface operable to couple at least a portion of the second band of light out of said second light emitting panel.  
     
     
       2. The illumination system of claims  1 , wherein the degree in which the at least a portion of the first band of light is coupled out of said first light emitting panel increases as a function of the distance between said light transmitting edge area and said first sub-surface. 
     
     
       3. The illumination system of  claim 1 , wherein the degree in which the at least a portion of the first band of light is coupled out of said first light emitting panel linearly increases as a function of the distance between said light transmitting edge area and said first sub-surface. 
     
     
       4. The illumination system of  claim 1 , wherein the degree in which the at least a portion of the first band of light is coupled out of said first light emitting panel decreases as a function of the distance between said light transmitting edge area and said first sub-surface. 
     
     
       5. The illumination system of  claim 1 , wherein the degree in which the at least a portion of the first band of light is, coupled out of said first light emitting panel linearly decreases as a function of the distance between said light transmitting edge area and said first sub-surface. 
     
     
       6. The illumination system of  claim 1 , 
       wherein a degree in which the at least a portion of the second band of light is coupled out of said second light emitting panel varies as a function of a distance between said second light transmitting edge area and said second sub-surface.  
     
     
       7. The illumination system of  claim 6 , 
       wherein said first sub-surface is further operable to project the at least portion of the first band of light on a first projected region; and  
       wherein said second sub-surface is further operable to project the at least portion of the second band of light on a second projected region.  
     
     
       8. The illumination system of  claim 7 , wherein at least a portion of the first projected region and at least a portion of the second projected region overlap. 
     
     
       9. The illumination system of  claim 7 , 
       wherein a projection area includes the first projection region and the second projected region; and  
       wherein a length of said first light emitting panel is less than a length of the projection area.  
     
     
       10. The illumination system of claims  1 , 
       wherein a projection area includes a plurality of projected regions;  
       wherein said first sub-surface is further operable to project the at least portion of the first band of light on a first projected region of the plurality of projected regions; and  
       wherein a length of said first light emitting panel is less than a length of the projection area.  
     
     
       11. The illumination system of  claim 1 , further comprising: 
       a sensor operable to measure an optical property of the first band of light,  
       wherein said fight light source emits the first band of light as a function of the measured optical property of the first band of light.  
     
     
       12. An illumination system for illuminating a display device, said illumination system comprising: 
       a first light source operable to emit a first band of light;  
       a first light emitting panel including a first light transmitting edge area operable to receive the first band of light, said first light emitting panel further including a first sub-surface on a first wall, said first sub-surface operable to couple it least a portion of the first band of light out of said first light emitting panel,  
       wherein a projection area includes a plurality of projected regions,  
       wherein said first sub-surface is further operable to project the at least portion of the first band of light on a first projected region of the plurality of projected regions, and  
       wherein a length of said first light emitting panel is less than a length of the projection area;  
       a second light source operable to emit a second band of light; and  
       a second light emitting panel including a second light transmitting edge area operable to receive the second band of light, said second light emitting panel further including a second sub-surface on a second wall, said second sub-surface operable to couple at least a portion of the second band of light out of said second light emitting panel,  
       wherein said second sub-surface is further operable to project the at least portion of the second band of light on a second projected region of the plurality of projected regions.  
     
     
       13. The illumination system of  claim 12 , 
       wherein a length of said second light emitting panel is less than the length of the projection area.  
     
     
       14. The illumination system of  claim 13 , wherein at least a portion of the first projected region and at least a portion of the second projected region overlap. 
     
     
       15. The illumination system of  claim 12 , 
       wherein a length of said second light emitting panel equals the length of the projection area.  
     
     
       16. The illumination system of  claim 15 , wherein at least a portion of the first projected region and at least a portion of the second projected region overlap. 
     
     
       17. The illumination system of  claim 12 , further comprising: 
       a sensor operable to measure an optical property of the first band of light,  
       wherein said fight light source emits the first band of light as a function of the measured optical property of the first band of light.  
     
     
       18. An illumination system for illuminating a display device, said illumination system comprising: 
       a first light source operable to emit a first band of light;  
       a first light emitting panel including a first light transmitting edge area operable to receive the first band of light, said first light emitting panel further including a first sub-surface on a first wall, said first sub-surface operable to couple at least a portion of the first band of light out of said first light emitting panel; and  
       a first sensor operable to measure an optical property of the first band of light,  
       wherein said fight light source emits the first band of light as a function of the measured optical property of the first band of light.  
     
     
       19. The illumination system of  claim 18 , further comprising: 
       a second light source operable to emit a second band of light;  
       a second light emitting panel including a second light transmitting edge area operable to receive the second band of light, said second light emitting panel further including a second sub-surface on a second wall, said second sur-surface operable to couple at least a portion of the second band of light out of said second light emitting panel; and  
       a second sensor operable to measure an optical property of the second band of light,  
       wherein said second light source emits the second band of light as a function of the measured optical property of the second band of light.  
     
     
       20. The illumination system of  claim 19 , further comprising: 
       a third source operable to emit a third band of light;  
       a third light emitting panel including a third light transmitting edge area operable to receive the third band of light, said third light emitting panel further including a third sub-surface on a third wall, said third sub-surface operable to couple at least a portion of the third band of light out of said third light emitting panel; and  
       a third sensor operable to measure an optical property of the third band of light,  
       wherein said third light source emits the third band of light as a function of optical property of the third band of light.